As severe climate events continue to wreak their havoc on the world, climate resiliency is becoming an essential consideration for designing buildings, so that they help to slow the pace of climate change and withstand the worst of its effects.
In this post, we will explain the principles of climate resilience and demonstrate them in action in a case study.
What Is Climate Resilience?
Climate resilience is a selection of strategies that help buildings mitigate climate risk.
Climate risk is the multifaceted hazard brought on by climate change. The formula below illustrates climate risk in straightforward terms:
Climate risk = Threat X Vulnerability
In the aforementioned formula, “threat” implies the risk of a climate change-caused weather event happening in a specific area. For example, living in the floodplain maximizes the risk of floods damaging structures.
Meanwhile, “vulnerability” describes the probability of damage occurring to buildings in a threat area during an adverse weather event.
For an example of the “threat” and “vulnerability” in action, look no further than the 2021 atmospheric rivers in the Pacific Northwest, which brought destruction to swathes of BC’s Lower Mainland. The historic floods damaged scores of communities in the floodplain of the Fraser River, and destroyed buildings and parts of critical infrastructure.
In this example, the “threat” was the risk of such an event occuring; the “vulnerability” was the structures’ inability to withstand the floods.
Together, these two variables combine to make up what we know as “climate risk.” And, to minimize climate risk in buildings, we must address both the threat and the vulnerability.
Addressing the Threat — Reducing Embodied and Operational Carbon in Buildings
Addressing the “threat” variable of the climate risk formula is no easy feat. Nobody knows for sure whether humanity will be able to slow or reverse climate change. However, this doesn’t mean that we shouldn’t try.
Climate change is tightly related to carbon emissions. In theory, with lower carbon emissions, the rate of global warming should slow. In construction, there are two primary ways for reducing carbon emissions.
Reducing Operational Carbon
The second way to reduce carbon emissions is to reduce the operational carbon of a building. Operation carbon refers to the CO2 emissions produced while the building is occupied. Buildings that emit less CO2 are those that are energy-efficient thanks to a combination of high-performance energy components and efficient mechanical systems.
Together, the reduction of embodied and operational carbon can limit the construction industry’s CO2 footprint and help, in part, to slow climate change.
Addressing the Vulnerability — Building Structures That Withstand Severe Weather
Addressing the “vulnerability” factor of climate risk is a bit more straightforward. After all, there’s more we can do to adapt to changing conditions than to reverse (or slow) the changing climate. In simple terms, addressing climate vulnerability means making buildings less susceptible to damage from severe weather events. Just as seismic force resisting structures protect buildings from earthquakes, various building systems and components can safeguard buildings from floods, hurricanes, and wildfires.
Apart from protecting a building from weather-related damage, it’s also essential to ensure passive survivability in the aftermath of a weather event.
Passive survivability refers to maintaining a reasonable level of comfort for a building’s occupants if the climate emergency knocks out the power. By achieving passive survivability, builders ensure that a home’s occupants can stay reasonably warm or cool in a prolonged power outage.
Now that we’ve discussed the concept of climate resilience, we will dive into a case study that shows one individual’s approach to achieving it with his own home.
In this case study, we will look at Bill Lett, an architect and homeowner in Peterborough, Ontario, who built his home with Logix ICF.
Below, we will explain how Bill’s home is designed and built with Climate Resilience principles in mind.
Reducing the Threat
Below are the two ways Bill’s home mitigates the “threat.”
1. The home is built with less embodied carbon
Switching from XPS to EPS insulation (the type used in Logix ICF walls) is a great way of reducing embodied carbon in a building because EPS contains less embodied carbon. By constructing his home with Logix ICF, Bill has taken a substantial step towards reducing his carbon footprint.
And this will only get more pronounced in the future — the new Biomass Balance (BMB) approach used by Neopor to manufacture EPS insulation in Europe. BMB entails mixing fossil-based and renewable resources at the start of the manufacturing process, and thus reduces EPS’ embodied carbon content by more than half. This BMB process is coming to North America in the next few years.
Likewise, while concrete production comes with a sizable carbon footprint, the industry is initiating changes that will make concrete production more green and reduce its carbon emissions
2. The home is energy-efficient
Logix ICF has three characteristics that improve a home’s efficiency. It’s these three properties that helped Bill construct a home that consumes as little energy as possible on heating and cooling:
- Logix ICF is airtight: The ICFs, along with a concrete core, make for an airtight wall assembly that virtually eliminates heat transfer through air movement.
- Logix ICF has no thermal bridging: ICFs provide a layer of continuous insulation on both sides of the concrete core. As such, they do not allow any thermal bridging to occur, and reduce heat transfer to a minimum.
- Logix ICF has a high thermal mass: Because of its high thermal mass, ICF walls take an extremely long time to let heat enter or exit a building. This crucial property means that a home can stay warm (or cool) longer if conditioning systems stop working during a power failure.
Reducing the Vulnerability
Here is how Bill reduced his home’s vulnerability to severe weather events.
1. Slash the risk of flooding
Bill’s house is above the 100 year floodplain but a corner of the property is within. As such, to meet the local conservation authority requirements, the basement of the house was “bath tubbed” so the risk of flood damage is mitigated. This involved not having any windows, sealing any service penetrations and using capillary breaks at the foundation wall connection to the footings.
2. Reduce vulnerability to risk from high winds
Apart from flooding, the highest threats for Bill’s home are strong winds that could cause trees and other objects to fall onto the home.
Strong winds can result in various debris impacting a building, and carry the risk of uplift forces damaging various components that protrude from the building. To mitigate these risks, Bill has chosen to build his home with 2 components that have a proven track record of disaster resilience — ICF walls and an ICF roof.
ICF walls include monolithic, reinforced concrete cores, which provide sufficient strength to resist impact from some of the flying debris. Such walls are also great at withstanding the lateral forces associated with strong winds.
An ICF roof helps protect the home from flying objects. Building the home’s walls with ICFs was not enough, because concrete walls do nothing to protect the comparatively fragile, wood-framed roof.
However, with an ICF roof structure, Bill’s home is ready to withstand falling trees or other debris that may be blown over by hurricanes or tornadoes. What’s more, with an ICF roof, the entire home structure was in sync, as all the vertical and horizontal structural members were made of concrete and any threat of roof uplift has been addressed.
And to mitigate damage to windows – the windows are protected by 5-foot overhangs and the fiberglass windows themselves are hurricane-resilient, as they’re strengthened with steel reinforcement.
To enhance passive survivability:
First of all, virtually the entire building envelope (walls, floors and roof) is high-mass concrete. As we mentioned above, Logix ICF has incredibly high thermal mass, and this property drastically slows the rate of heat transfer between the home’s interior and exterior when a sudden temperature occurs.
For example, if the home’s air conditioning system cuts out while it’s 100F outdoors, ICF walls would prolong the time it took the outside heat to make its way inside.
The same concept applies in winter, if the heating system abruptly stopped working while outdoor temperatures were far below the freezing mark. In such an event, Bill’s home’s ICF walls would keep the interior warm and comfortable for a long time.
The home also gets heated with hydronic radiant floor heating in concrete floors. In this setup, there’s a natural gas boiler that heats water and a circulator pump that cycles the hot water beneath the concrete floors (the floors also slow heat transfer due to their high thermal mass).
And finally, in the event of a power loss, the house is equipped with a natural gas backup generator, which can supply much-needed electricity until service is restored.
Wrapping It Up
Driven by climate change, adverse weather events are causing more and more damage to our buildings every year.
To adapt to this new normal, we need to use climate resiliency strategies in construction. Climate resiliency methods can both contribute to slowing the pace of climate change and make our buildings more resilient and less susceptible to damage.
As you’ve seen from our case study, a single individual can take matters into their own hands and build with climate resiliency in mind.